Abstract: In this study, the analysis on clustering and evolutionary trends using mathematical algorithms was carried out to assess former taxonomic treatment and evolutionary trends within the species. The results showed that infraspecific taxa of V. negundo L. were divided into two groups: one with spreading inflorescence including forma laxipaniculata and forma alba, the other with narrow inflorescence including the other five varieties. The inflorescence character shows some taxonomic value, and reduction of forma laxipaniculata and forma alba to the synonyms of V. negundo was not supported. By comparison between the primitive and derived characters infraspecific taxa within the V. negundo L. were recognized and evolutionary trends were assessed. Vitex negundo var. negundo is detected to be the most primitive taxon in the species complex and its morphological characters may have evolved toward four directions, e.g., from integrate leaf margin to lobed leaf margin, large leaflets to relatively small leaflets, glabrous leaf blade to hairy leaf blade, narrow inflorescence to spreading inflorescence, and finally forming the current patterns of infraspecific taxa and their distribution. This paper also reported new geographical distributions of V. negundo var. negundo in eastern Hebei Province and new pinnately lobed leaflet character of V. negundo var. heterophylla.